This invention relates in general to vehicular brake systems, and in particular is concerned with control valves mounted in a hydraulic control unit of an electronically controlled brake system.
Electronically-controlled brake systems for vehicles are well known. One type of electronically-controlled brake system includes a hydraulic control unit (HCU) connected in fluid communication between a master cylinder and a plurality of wheel brakes. The HCU includes a housing containing control valves and other components for selectively controlling hydraulic brake pressure at the wheel brakes.
Control valves for HCU""s are commonly formed as electronically actuated solenoid valves. A typical solenoid valve includes a cylindrical armature slidably received in a sleeve or flux tube for movement relative to a valve seat. A spring is used to bias the armature in an open or closed position, thereby permitting or blocking fluid flow through the valve, respectively. A coil assembly is provided about the sleeve. When the valve is energized, an electromagnetic field or flux generated by the coil assembly slides the armature from the biased open or closed position to a closed or open position, respectively.
Control valves mounted in an HCU are actuated by an electronic control module to provide desired braking functions such as anti-lock braking, traction control, and vehicle stability control.
This invention relates to control valves mounted in a hydraulic control unit of a vehicular brake system. Each control valve can be configured as a normally open valve or a normally closed valve. Identical components are shared between the two configurations. A method of economically assembling the control valves as subassemblies reduces conventional costs associated with such subassemblies. A method of assembling the control valves on a hydraulic control unit reduces conventional costs associated with such assembly.
In a preferred embodiment, a method for assembling a hydraulic control unit of a vehicular brake system includes the following steps of: providing a sleeve having a closed end; sliding a spring over an armature to form an armature/spring subassembly; orientating the armature/spring subassembly to produce a normally open valve or a normally closed valve; sliding the oriented armature/spring subassembly into the sleeve; sliding a valve seat into the sleeve; crimping a portion of the sleeve onto the valve seat to form a sleeve/valve seat subassembly; inserting the sleeve/valve seat subassembly into a bore of a housing.
Two additional steps can be combined with the above listed steps to provide a method of assembling the control valve subassemblies described above on a hydraulic control unit. The additional steps include: inserting the sleeve/valve seat subassembly into a bore in a housing; and pressing a coil assembly about the sleeve.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.